Air-conditioning systems are known with a central control device, and air-conditioning devices such as outdoor devices, indoor devices and the like are connected in parallel, and the central control device controls the air-conditioning devices (for example, see Japanese Patent Literature 1).
An air-conditioning system can form a networked air-conditioning system by expanding the air-conditioning system by connecting an air-conditioning system (upper-level air-conditioning system) that is connected to an upper-level bus, and air-conditioning system (lower-level air-conditioning system) that is connected to a lower-level bus. In a networked air-conditioning system that the communication methods for the upper-level air-conditioning system and the lower-level air-conditioning system are different in, the case of performing individual control of an air-conditioning device in a lower-level air-conditioning system from the upper-level air-conditioning system will be considered. In this case, it is necessary to provide a new function in the air-conditioning devices of the lower-level air-conditioning system for performing communication with the upper-level air-conditioning system. Furthermore, the upper-level air-conditioning must be able to specify an air-conditioning device of a lower-level air-conditioning system that is to be the target of control.
Therefore, a system is disclosed that connects an upper-level air-conditioning system and a lower-level air-conditioning system by providing a converter between the bus of an upper-level air-conditioning system and the bus of a lower-level air-conditioning system (for example, see Japanese Patent Literature 2).
The converter disclosed in Japanese Patent Literature 2 has a protocol conversion function. The converter receives a control command with the address of an air-conditioning device that is to be the target of control, interprets that control command through a protocol converter, and converts the communication method. With this converter, it becomes possible to perform communication between networks that have communication methods that are different from each other, and it becomes possible to perform individual control of an air-conditioning device in a lower-level air-conditioning system from an upper-level air-conditioning system.